One type of a cab stopper device proposed for work machines, for example, is the structure disclosed in Patent Document 1. In this conventional device, a block-like stopper member is fixed to a side portion of the cab. A receiving member is secured to the machine frame and projects from the frame. The receiving member includes an engaging recess, which is engageable with the stopper member. The stopper member faces the inner surface of the engaging recess, and a clearance is formed between the stopper member and the inner surface of the engaging recess. According to this structure, when the cab moves relative to the machine frame, the engagement between the stopper member and the receiving member inhibits the cab from moving relative to the machine frame by an amount more than or equal to a predetermined distance.    Patent Document 1: Japanese Laid-Open Patent Publication No. 2007-162234